The present invention relates generally to thin flexible substrates such as those used to fabricate flexible devices. More particularly, the invention relates to the stress (bending) testing of thin glass substrates.
To access the flexibility of thin substrates, bending tests have to be performed. During these tests, the substrate is subjected to bending until it breaks. The shards have to be reconstructed for the analysis to determine the breaking behavior.
The shards are not held together but are scattered after the breakage and have to be collected and fitted back together. This process of reconstruction is time-consuming. Furthermore, it is not always possible to fit all the shards back to their original positions as the shards are small and numerous, and scatter randomly in many different directions.
As evidenced from the above discussion, it is desirable to facilitate the reconstruction process by providing a means to keep the shards together after breakage.
The invention relates generally to thin flexible substrates, such as those used in microelectronics, optoelectronics and display devices. In particular, the invention facilitates the stress testing of flexible substrates like thin glass substrates. The present invention can also be used to facilitate stress testing of non-flexible substrates like silicon chips, chips of compound semiconductors or wafers as well as glass.
In accordance with the invention, a support is provided to keep the shards of the substrate together after breakage. In one embodiment, the support comprises a plastic layer attached to one side of a substrate. Alternatively, the plastic layer can be applied to both sides of the substrate. The plastic layer can be laminated on the substrate with an adhesive. Using plastic layer which includes an adhesive or comprises adhesive properties can also be used. Such plastic layers are referred to as, for example, adhesive plastic layers. Alternatively, the plastic layer is deposited using deposition techniques such as spin-coating or spraying. Subsequently, the substrate with the support undergoes a bending test until it shows a failure.
The shards are kept together by the plastic layer after breakage, and it is no longer necessary to collect the small shards and fit them back together. Hence, a more precise and efficient failure analysis of the flexible substrate can be done.